pub fn dp_rec_mc(amount: u32) -> u32 {
    // 可用的纸币面值，从大到小排序
    let money = [100, 50, 30, 20, 10, 5, 2, 1];
    //剩余金额
    let mut remaining_amount = amount; 
    //使用的纸币数量
    let mut coin_count = 0;

    //优先使用大面值的纸币
    for &coin in &money {
        while remaining_amount >= coin {
            remaining_amount -= coin;
            coin_count += 1;
        }
    }

    coin_count
}